In a leaked letter sent to Spain's outgoing President, the US ambassador to the country warned that as punishment for not passing a SOPA-style file-sharing site blocking law, Spain risked being put on a United States trade blacklist . Inclusion would have left Spain open to a range of "retaliatory options" but already the US was working with the incoming government to reach its goals.

United States government interference in Spain’s intellectual property laws had long been suspected, but it was revelations from Wikileaks that finally confirmed the depth of its involvement.

More than 100 leaked cables showed that the US had helped draft new Spanish copyright legislation and had heavily influenced the decisions of both the government and opposition.

Now, another diplomatic leak has revealed how the US voiced its anger towards outgoing President Jose Luis Rodriguez Zapatero last month upon realizing that his government was unlikely to pass the US-drafted Sinde (site blocking) Law before leaving office.

In a letter dated December 12th and sent by US Ambassador Alan D. Solomont to the Spanish Prime Minister’s office, the US expressed “deep concern” over the failure to implement the SOPA-style censorship law.

“The government has unfortunately failed to finish the job for political reasons, to the detriment of the reputation and economy of Spain,” read the letter obtained by El Pais.

Racing against the clock in the final days of the government, Solomont had one last push.

“I encourage the Government of Spain to implement the Sinde Law immediately to safeguard the reputation of Spain as an innovative country that does what it says it will, and as a country that breeds confidence,” he wrote.

But along with the pleas came the stick.

In the letter, which was also sent to Minister of Culture Ángeles González-Sinde after whom the law is named, Solomont noted that Spain is already on the Special 301, the annual report prepared by the Office of the United States Trade Representative (USTR) detailing ‘trade barriers’ based on intellectual property issues.

Solomont’s threat was that should Spain not pass the Sinde Law (described by some as the Spanish SOPA) then the country would be degraded further and placed on the Priority Watch List. This serious step would mean that Spain was in breach of trade agreements and could be subjected to a range of “retaliatory actions”.

In the event Zapatero’s government left office without passing the law, but the incoming Partido Popular (People’s Party) were quickly pressured by the US to take the necessary action.

In another media leak it’s now been revealed that American Chamber of Commerce in Spain chief Jaime Malet wrote a cautionary letter to incoming Spanish Prime Minister, Mariano Rajoy. He warned of the potential flight of foreign investment from Spain and urged him to take action on the protection of intellectual property once in office.

“[The law’s] lack of approval before the elections has been a blow to the country’s seriousness in this matter of such importance,” said Malet, while urging Rajoy to “to retrieve the consensus reached.”

Rajoy’s government quickly responded and fully implemented the legislation within 10 days of taking office.